The fees, mandated by state legislation approved last year, are being required of Maryland's nine largest counties and Baltimore City to pay for measures to help keep pollutants carried by stormwater runoff out of the Chesapeake Bay.

In March, Howard's council approved a plan that involved a calculation for every property — residential and commercial — based on the area of impervious surfaces such as driveways, parking lots and rooftops.

But last month, County Executive Ken Ulman proposed an alternative that he described as a "simpler, more fair way to move forward."

Howard's residential stormwater fees will be $15 a year for townhouses and condominiums, $45 for single-family homes on lots up to a quarter of an acre and $90 for homes on properties larger than a quarter-acre. For commercial apartments, the fee will be $15 per apartment unit.

For non-residential properties, the new plan continues to calculate the fee based on impervious surface area, with a fee of $15 per impervious unit.

However, for non-residential property owners who would owe more than $10,000 in 2014, the fee will be the greater of 50 percent of the charge or $10,000. After 2014, non-residential property owners will have to pay the full fee.

Hardship options for non-residential property owners could reduce the fee by up to 20 percent of the property's annual property tax bill.

The state had said jurisdictions had to have a fee structure in place by July 1, but Howard County held off charging them until Ulman's proposal and other amendments could be considered.

County officials said last month that they would hold off billing for the stormwater fees until the second round of property tax bills goes out in December.

An amendment designed to address concerns that religious and non-profit institutions would be overburdened by the tax set up a system to evaluate these properties, provide grants to help control stormwater on the property and then provide credits for these stormwater management practices that could cover up to the entire cost of the fee.

The fees have been characterized by critics as a "rain tax." While the fees are mandated by the state, individual jurisdictions may devise their own structure and rates.

In Baltimore County, for instance, homeowners will pay a flat fee of $21 to $39, while owners of commercial properties pay based on the amount of impervious surface. Carroll County opted to use grants and county dollars to fund projects instead of charging residents directly.

A little more than a week before the stormwater fee — approved by the Howard County Council in March — was set to take effect, County Executive Ken Ulman introduced a model described as simpler and more efficient.